2960 switch down

[jai.s401]

The L2 switch went down i.e all the end users had disconnected from the network, No network symbol.

After 5 minutes plugging and unplugging the uplink port the network came Up.

Don't know if it came up because of unplug and plugging uplink

and found only the below logs :

Syslog logging: enabled (0 messages dropped, 1 messages rate-limited, 0 flushes, 0 overruns, xml disabled, filtering disabled)

No Active Message Discriminator.

No Inactive Message Discriminator.

Console logging: level debugging, 5020 messages logged, xml disabled,
filtering disabled
Monitor logging: level debugging, 0 messages logged, xml disabled,
filtering disabled
Buffer logging: level debugging, 5020 messages logged, xml disabled,
filtering disabled
Exception Logging: size (4096 bytes)
Count and timestamp logging messages: disabled
File logging: disabled
Persistent logging: disabled

No active filter modules.

Trap logging: level informational, 5022 message lines logged
Logging Source-Interface: VRF Name:

Log Buffer (4096 bytes):
down
May 17 18:24:20.907: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to up
May 17 18:24:21.956: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to up
May 17 18:24:22.917: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to up
May 17 18:29:10.052: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to down
May 17 18:29:11.010: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to down
May 17 18:29:12.013: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to down
May 17 18:29:15.253: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to up
May 17 18:29:16.340: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to up
May 17 18:29:17.263: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to up
May 17 18:29:31.778: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to down
May 17 18:29:32.740: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to down
May 17 18:29:33.743: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to down
May 17 18:29:39.503: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to up
May 17 18:29:41.418: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to up
May 17 18:29:41.513: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to up
May 17 18:29:45.221: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to down
May 17 18:29:46.179: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to down
May 17 18:29:47.186: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to down
May 17 18:29:53.861: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed st ate to up
May 17 18:29:55.504: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, chan ged state to up
May 17 18:29:55.871: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe rnet1/0/48, changed state to up
May 17 18:30:07.724: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
May 17 18:30:08.699: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to down
May 17 18:30:09.705: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to down
May 17 18:30:28.461: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to up
May 17 18:30:31.023: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to down
May 17 18:30:39.101: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to up
May 17 18:30:41.110: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to up
May 17 18:30:41.823: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
May 17 18:30:51.299: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
May 17 18:30:52.260: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to down
May 17 18:30:53.267: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to down
May 17 18:30:56.619: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to up
May 17 18:30:57.922: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
May 17 18:30:58.632: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to up
May 17 18:31:08.366: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
May 17 18:31:09.341: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to down
May 17 18:31:10.348: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to down
May 17 18:31:13.585: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/48, changed state to up
May 17 18:31:14.686: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
May 17 18:31:15.598: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/48, changed state to up

48th port is the trunk port to core switch.

cleared the interface counters and checked after that no CRC error Occured after that.

why the Interface vlan goes down ?

How can i troubleshoot this ?

How can i find route cause of this issue and prevent it from happening in future.

[MHM Cisco World]

can you share 
show spanning tree vlan X

[Reza Sharifi]

Was the switch rebooted? What is the output of "sh ver"?

HTH

[SinghRaminder]

Any specific logs on the Core?
What is vlan 1 used for? Is it only part of int 48, if thats the case, port 48 going down will make vlan 1 down as well
Any layer 1 issue? Bad cable?

logs from other side can be helpful in this case

[MHM Cisco World]

UP then down it may cause of STP Loop, so we need to see the 
show spanning tree vlan x

[Leo Laohoo]

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@jai.s401 wrote:

After 5 minutes plugging and unplugging the uplink port the network came Up.

---

<FACEPALM>

Post the complete output to the command "sh interface Gi1/0/48 controll". 

[jai.s401]

I have attached the log of core switch #core and the switch which had a issue #switch 1"   

according to the user the complaint is as below:

 ""one of the switches in  got disconnected. When we observed physically the switch having power , all the ports are having green lights on , but devices not having traffic. After some time without any troubleshoot , all the devices got connected. ""

I have cleared the counters and after 10 hrs CRC errors observed in interfaces.

But when i run the TDR test, it shows the pair is normal. (attached in log)

please go through the log and guide me.

[Leo Laohoo]

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@jai.s401 wrote:

I have cleared the counters and after 10 hrs CRC errors observed in interfaces.

---

That is not the output I have requested.  

[jai.s401]

I have included the logs that you have requested. If that doesn't help. please mention the specific command for required log.

[marce1000]

 - Connect to your device (SSH) with : https://cway.cisco.com/cli/  . at the top left run or Press 'System Diagnostics' and also at the top right press 'Crashdump Analyzer'

 M.

[jai.s401]

Hi marce,

The requested log file is : 172.16.1.47 is the required log file.

additionally i have Attached the log of another switch which issue of " host disconnecting randomly connecting in a specific port"

please go through it and find me a way through.

[Leo Laohoo]

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@jai.s401 wrote:

I have included the logs that you have requested. If that doesn't help. please mention the specific command for required log.

---

Last request:  Post the complete output to the command "sh interface Gi1/0/48 controll". 

[jai.s401]

Is the above command different one from " show interface Gi1/0/48 controller"  ?????

[jai.s401]

Hi leo,

Here is the log required.

pls go through and give a root cause.

[Leo Laohoo]

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@jai.s401 wrote:

800 FCS errors 

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Confirm this is a layer 1 issue.